Prevention of hyperthermia with silk of the oriental hornet, Vespa orientalis: a hypothesis

Wasps apparently develop normally even under extreme thermal conditions, including deserts. We deemed it worthwhile to set up an experiment wherein wasp brood combs containing a full gamut of brood ranging from eggs up to pupae and a few adults were kept in an incubator whose temperature was gradually raised to 45 degrees C, and the response of the disparate brood to such warming was photographed via Infra Red camera. The finding of this experiment showed that for open brood (i.e., eggs, larvae at various instars, and empty cells) the temperature was close to the ambient temperature, but in the silk coated pupae, the temperature was lower than the ambient by up to 4 degrees C. This lower temperature was retained for at least 90 min of incubation. For comparison we evaluated the relative contribution of the pupae to the phenomenon, by warming also a vacant, (i.e., a broodless and silkless comb) in parallel to a comb from which the pupae had been extricated but the silk weave retained and left behind. We found that the totally empty comb heated up under these conditions to nearly 110 degrees C, whereas the silk-containing vacant cells only heated up to about 40 degrees C. These finding are discussed from two aspects, namely the importance for wasps to maintain a constant temperature throughout the pupating process, and the manner in which the silk weave contributes to such a goal.     

Presence of a thermoregulatory hot spot in the prothorax of the large carpenter bee and the bumble bee

In both the large carpenter bee (Xylocopa pubescens) and the bumblebee (Bombus terrestris), a hot spot was detected in the center of the prothorax on its dorsal-external aspect. In both cases, the temperature in this hot spot was found to be greater than the ambient temperature and that at the tip of the gaster. In B. terrestris, it was higher by 9-10 degrees C from that at the gaster tip and by 15-16 degrees C from the ambient temperature, while in X. pubescens the corresponding differences were 11-20 degrees C and 18-19 degrees C, respectively. The recorded thermal differences were not fixed but were rather variable, temporally as well as individually, but invariably all individuals measured showed these temperature differences. Furthermore, in none of the studied specimens was a hot spot detected in any part of the body other than the prothorax. From this hot spot in the prothorax, there is a cascade of temperatures in both directions, that is, anteriorly towards the head and posteriorly towards the gaster, with a graded drop in temperature in either direction. This article discusses possible reasons for the existence of such a hot spot in this particular location (the prothorax), its role or function, and its mode of operation. The authors speculate that it is a thermoregulatory center (for heating or cooling) that might be present in possibly all Hymenoptera that spend a considerable part of their life flying, regardless of whether they are social, parasocial, or solitary.     

Large-Area Freestanding Bi2S3 Nanofibrous Membranes for Fast Photoresponse Flexible IR Imaging Photodetector

Films with excellent flexibility and mechanical stability are important for flexible and wearable devices. However, most films reported are prepared on substrates, and the synthesis of freestanding flexible films remains a challenge. Herein, a freestanding Bi₂S₃ nanofibrous membrane (NFM) is successfully prepared via a one-step hydrothermal method, which is self-assembled from ultralong Bi₂S₃ nanowires (NWs) over a length of millimeter-scale crisscrossing each other. Significantly, the Bi₂S₃ NFM can be bent or clipped into an arbitrarily desired form. Based on the freestanding Bi₂S₃ NFM, an IR photodetector is fabricated, depicting a robust responsivity of 2.23 (2.06) µA W⁻¹ under 850 (940) nm illumination. The Bi₂S₃ NFM photodetector exhibits a relatively fast response time (47.1 ms), which is attributed to high-speed carrier transport efficiency in the NWs network. Under the bending states, the device still exhibits excellent detection performance, maintaining more than 86% of the initial photocurrent even after 1000 bending-flattening times. The robust photoresponse of the Bi₂S₃ NFM photodetector after 2 months of storage in air and after 1 week in the bending state illustrates its excellent air stability and flexible detection ability. Besides, the photodetector can clearly identify the target image, indicating widespread potential applications in flexible and wearable fields.     

Improved In Situ Characterization of Electrochemical Interfaces Using Metasurface-Driven Surface-Enhanced IR Absorption Spectroscopy

Electrocatalysis plays a crucial role in realizing the transition toward a zero-carbon future, driving research directions from green hydrogen generation to carbon dioxide reduction. Surface-enhanced infrared absorption spectroscopy (SEIRAS) is a suitable method for investigating electrocatalytic processes because it can monitor with chemical specificity the mechanisms of the reactions. However, it remains difficult to detect many relevant aspects of electrochemical reactions such as short-lived intermediates. Herein, an integrated nanophotonic-electrochemical SEIRAS platform is developed and experimentally realized for the in situ investigation of molecular signal traces emerging during electrochemical experiments. A platinum nano-slot metasurface featuring strongly enhanced electromagnetic near fields is implemented and spectrally targets the weak vibrational mode of the adsorbed carbon monoxide at ≈2033 cm⁻¹. The metasurface-driven resonances can be tuned over a broad range in the mid-infrared spectrum and provide high molecular sensitivity. Compared to conventional unstructured platinum films, this nanophotonic-electrochemical platform delivers a 27-fold improvement of the experimentally detected characteristic absorption signals, enabling the detection of new species with weak signals, fast conversions, or low surface concentrations. By providing a deeper understanding of catalytic reactions, the nanophotonic-electrochemical platform is anticipated to open exciting perspectives for electrochemical SEIRAS, surface-enhanced Raman spectroscopy, and other fields of chemistry such as photoelectrocatalysis.     

Rapidly Modulated Wide-Spectrum Infrared Source Made of Super Aligned Carbon Nanotube Film for Greenhouse Gas Monitoring

Non-dispersive infrared (NDIR) gas monitoring has advantages of environment stability, convenient operation and maintenance, wide detection range, and multi-gas-detection capability. However, the conventional IR sources for NDIR gas monitoring, such as miniature lamps, microelectromechanical system (MEMS) light sources, and light-emitting diodes (LEDs), can only work at narrow modulation frequency and spectral range, or require complicated design and fabrication, because of the constraint of materials and work principle. These issues cause low data acquisition rate, poor anti-interference ability and limited gas compatibility to NDIR. Here, the super-aligned carbon nanotube (SACNT) film is developed as an IR source in NDIR gas monitoring system. It has a wide spectral range (0.2–334 µm), a facile fabrication method, and can work up to a high frequency ≈150 kHz. A mechanical-chopper-free and wide-concentration-range monitoring equipment for CO₂ and CH₄ greenhouse gases is demonstrated with SACNT film IR source. The concentration ranges for CO₂ and CH₄ investigated in this paper are 0.0195–20.10% (v/v) and 0.10–17.11% (v/v), respectively. It can be easily applied to monitor other kinds of gases as well.     

X70超低硫管线钢中有害元素的控制

介绍了在X70钢工业试验研究中，采用两种工艺路线成功地生产了6炉X70钢。并且通过对比确定最佳工艺路线和操作工艺参数以及对有害元素的控制措施，为今后批量生产提供了可靠依据。     

数据融合在目标对载机准确定位中的应用

基于卡尔曼滤波的数据融合理论在机载光电跟踪系统中的应用，建立目标对载机准确定位的物理模型和极坐标下的数学模型，研究观测值加权融合、观测状态向量合并和状态估计融合反馈三种算法，并进行协方差分析比较，仿真实验结果表明，观测值融合算法的性能优于其它算法。     

基于刻面分类的信息检索匹配优化探讨

信息检索是指信息按一定的方式组织起来,并根据信息用户的需要找出有关的信息的过程和技术。通过软件构件刻面,允许构件通过提供不同的接口为客户端提供不同的视图。信息检索从其最终的算法实现上来看,都可以划分成两个部分--控制结构和产生系统,而所有的算法的优化和改进主要都是通过修改其控制结构来完成的。本文利用探针后台接收客户端用户的请求,通过访问刻面分类的信息检索获得用户需要的信息,以此实现信息检索中匹配优化。     

IR2110在IGBT驱动电路中的应用

针对IGBT的半桥或者全桥的驱动,利用具有双通道集成驱动的IR2110来驱动IGBT.对其自举工作原理进行了分析,同时增加了栅极电平箝位电路,克服了IR2110不能产生负偏压的缺点,并在2 kW、400 V汽车直流充电器中以此驱动IKW40N120T2电路的试验中验证了其理论分析的正确性.     

综合利用各类信息的红外/雷达数据关联

异类传感器数据关联是数据融合中的一个难点,综合利用角度和其他特征信息是改善异类传感器数据关联的一个重要途径.对于雷达在直角坐标系对目标进行跟踪、红外传感器在修正的球坐标系对目标进行跟踪情况,文章综合利用角度、角度变化率和ITG(Inverse-Time-to-Go)信息,构建了新的关联统计量,并进行了计算机仿真.结果表明,所给出的新关联统计量较之只利用角度或角度变化率的关联统计量有更好的关联性能.